Thermally actuated regulator for heaters



Jul 10, 1934.

o. J. KUENHOLD 1,966,098 THERMAL-LY ACTUATED REGULATOR FOR HEATERS FiledAug. 12, 1929 III/llllIl/IIIIIl/II/IlII: yzzlllllllll llllljyy g 46Patented July 10, 1934 UNITED STATES THERMALLY ACTUATED HEATER.

Otto J. Kuenhold, Cleveland, Ohio, assignor to H. M. SheerCompany,Quincy, 11]., a corporation of Illinois Application August 12, 1929,Serial No. 385,138 26 Claims. (01. 236-99) This invention relates tomeans for thermostatically regulating the quantity of fluid-fuelsupplied to a room heater.

Thermallycontrolled valves are not new and the present invention ismerely an improvement in various particulars over thermally controlledregulators heretofore produced.

One object of my improvement is to produce a regulator which respondsvery quickly to slight changes in temperature, and another object is toobtain large variations in the flow of fuel to the heater 'without theaid of mechanism which produces rubbing friction between its parts. Iprovide a dial bearing numerals representing various temperatures withinthe range of the instrument, and associated with this dial is a pointermovable to point to any temperature indicated on the dial. One of myobjects is to correlate the spacing of the numerals on the dial and themovements of the pointer to the'action of the thermally actuatedelement, so that the room temperature will be maintained atsubstantially that to which the pointer is directed, and as one means ofeflecting this result I provide for moving the dial itself, by way ofinitial adjustment, so as to bring into registration with the pointerthe numeral on the dial which represents the actual temperature of theroom at the time. The dial is then fixed in this position to prevent itsaccidental displacement. Provision is made to prevent injury to thethermal element, or other parts of the instrument, by excessive movementof the pointer. I also provide for reducing variation in the action ofthe thermally actuated element due to variations in the weight of theatmosphere.

I shall now proceed to describe the construction of my thermallycontrolled valve, and its operation,-with the assistance of theaccompanying drawing, in which Fig. 1 isa sectional elevational view ofthe complete instrument, and

Fig. 2 is a view of the device looking downward at it.

The body of the instrument, indicated generally by the numeral 10,contains a chamber 11, which, through an opening 12, is connected to asupply pipe. The opening 12 is a tapped hole in a boss formed on thebody and the gas supply pipe is screwed into this hole. If desired asimilar boss may be provided on the side opposite, that is, the sidewhich, in the drawing, has been removed to exhibit the interior, so thesupply pipe can be connected to either side of the body, the unused holebeing closed with a threaded plug.

A second chamber, 13, alongside of chamber 11, is to be connected by asuitable pipe to the heater, which is not shown. Chambers 11 and 13 areconnected by a by-pass 14 through which a limited quantity of gaspasses, according to the position of the regulating screw 15.

The top part of the body 10 comprises a flat member 16 which issurmounted by a low circular wall 17, forming a shallow basin-likechamber 18. This chamber is covered by a circular plate 19, which has alow circular flange 20 of the same diameter as the flange 17. This plateis secured to the member 16 by screws 29, and clamped between theflanges 17 and 20 is a soft leather diaphragm 21. The chambers 13 and 18are permanently connected by a port 22, making these chambers in effectone chamber, of which the diaphragm 21 is one wall. Further notice willbe taken of this point presently.

The chambers 11 and 18 are connected through a valve, of which thediaphragm 21 is one member. The other member of the valve is an annularring 23, which is set in and extends upward from the top 16 of the body,and forms a seat on which the diaphragm rests to close the valve. Thespace or chamber 24 encircled by the ring 23 is separated from thechamber 11 by the top 16, but a hole 25 in the top 16 permanentlyconnects the two chambers. This hole is of a rather small size, for areason which will be mentioned presently. While the diaphragm might bemade to seat directly on the ring 23, I prefer to secure a metal disc 26to each side of the diaphragm, and on the lower disc place a softleather disc 27, the latter being the member which actually comes incontact with the valve seat 23. These discs are secured to the diaphragmwith a rivet having a round head 28. If desired the upper one of thediscs 26 may be omitted. The object of providing the disc 27 is thatshould the ring 23 wear through the leather disc the only harm donewould be a small leakage of gas past the valve when the valve is closed.If the diaphragm itself became worn through gas would escape into theroom. The valve 21-23 is opened by pressure of the gas in the chamber24, assisted by the small gas pressure in chamber 18. This will befurther referred to presently.

I shall now describe the thermally actuated part of my device. Securedto the plate 19 by screws 30 is a cover or housing 36, within which thethermally actuated element 37 is mounted between a spring 38 and thepoint of an adjusting screw 39, which is screwed into the top of thehousing 36. The element 37 is of the well known thermo-bellows-diaphragmtype, and comprises two circular thin metal discs, and 41, each of whichis depressed, so that when they are united face to face with their edgesin contact, and soldered together, they form a comparatively thin closedchamber. This chamber is filled, preferably, with a vapor whichliquefies at a temperature somewhat below the intended temperature rangeof the instrument. This vapor expands under the action of heat, pressingthe discs 40 and 41 apart more or less, bellows-fashion, thereby varyingthe thickness of the element in the manner well known and understood indevices of this type.

The spring 38 is made of a strip of sheet metal, its ends being securedto the under edge of the housing 36 by screws 42, the heads of whichscrews extend into holes in the plate 19. At its center the springcarries a boss 43 having a socket which receives a stud 44 extendingdownward from the disc 41. The tension of the spring is upward, therebylifting the thermal element and pressing it against the end of theadjusting screw 39. The disc 40 has a conical depression in its center,which the point of the screw enters. Therefore, the thermal element issupported in a sort of floating relationship between the spring 38 andthe screw 39 which causes the movements of the thermal element to occurin a line that passes through the centers of the discs 40 and 41 of saidelement. The boss 43 extends downward from the spring a suificientdistance to pass through a hole 45 in the plate 19 and bear on the rivethead 28. Assuming the screw 39 has been properly adjusted, it is obviousthat as the thermal element 37 expands the diaphragm 21 will be pressedtoward the seat 23 more or less, according to the temperature of theatmosphere surrounding the thermal element, and even press the leatherdisc 27 to the seat 23 if the expansion of the thermal element is greatenough, thus closing the valve entirely. The flat bottom of the boss 43resting upon the round head of the rivet 28 provides a connectionbetween the diaphragm 21 and the thermal element in the nature of auniversal joint, and insures level seating of the diaphragm on the seat23. Referring to the drawing it will be noticed that between the boss 43and each of its ends the spring 38 is curved. This is to enable the bossto pass a central position without a tendency on the part of the springto snap above or below the center. The housing 36 is provided withnumerous openings 46 to permit free circulation of air around thethermal element, thereby effecting great sensibility to temperaturechanges. The hole 45 is enough larger than the boss 43 to prevent thelatter touching the sides of the former, thus avoiding frictionalresistance to the movement of the boss.

The top of the housing 36 is rabbeted to receive a circular dial 50.This dial is concentric to the adjusting screw 39, and it carriesgraduations, preferably numerals, representing various temperatureswithin the range of the instrument. The

screw 39 terminates in a knurled knob 51, from one side of which apointer 52 projects. A pin 53 is set in the dial in the path of thepointer 52, to prevent the screw being turned more than one revolution.The pitch of the screw and spacing of the dial numerals are coordinatedwith the coefficient of expansion of the thermal element, so that ifwith the pointer set at a numeral representing a given temperature theroom is maintained at that temperature, the room can be maintained atany other temperature within the range of the instrument by merelyturning the screw to bring the pointer to the numeral rep resenting thedesired temperature. A compression spring 55 confined between the knob51 and the housing holds the screw frictionally and prevents accidentaldisturbance of. the screw after it is adjusted.

In order to adjust my regulator to local conditions, such as rooms ofdifferent sizes, heaters of different sizes, different gas pressures,etc., I provide for rotating the dial with reference to the housing 36.Two clamping screws 54 are provided for securing the dial in a desiredposition. After the heater is installed and connected up, its burner islighted and the screw is adjusted so the room atmosphere is brought toand maintained at the temperature most commonly used. Then the dial isrotated to bring into registration with the pointer the numeral whichrepresents the temperature of the room at the time, and secured in thatposition with the screws 54. Thereafter it is only necessary to turn theknob 51 to bring the pointer to the numeral representing a temperaturewhich it is desired to maintain in the room, and the regulator willmaintain the desired temperature.

The graduations on the dial 50 are differentially spaced to conform tothe varying amount of expansion of the vapor-filled thermal element atvarious temperatures. It will be noted that in Fig. 2 of the drawing thenumerals representing degrees progressively increase their relativeangular positions at increasing temperatures. If, for instance, atemperature of is maintained, the pointer must be moved through agreater angle to increase the temperature 10 than to decrease it 10".Others before me have noted the varying rate of expansion per degree oftemperature change at various temperatures in the bellows type expansionelements, but apparently it has not occurred to others that a dialdifferentially spaced could be rotated for calibration or adjustmentpurposes to bring the graduation on the dial which represents thetemperature actually maintained in the room into registration with thepointer, and that thereafter any desired temperature within the range ofthe instrument could be accurately maintained simply by turning thepointer to the desired temperature.

One object of the by-pass 14 is to prevent extinction of the heaterburner. By means of the by-pass screw 15 the flow of gas to the chamber13 can be reduced to any desired amount, even to the minimum need of theheater burner. Another function of the by-pass is to maintain gaspressure, small though it be, under the diaphragm 21 when the valve isclosed. This is effected through the port 22, which port is for thatreason of liberal size, making the chambers 13 and 18 in effect onechamber, and it tends to equalize the amount of pressure necessary toclose the valve 21-23 and that required to hold the valve shut after itis closed. If there were no by-pass, and consequently no pressure in thechamber 18 when the valve 2123 is closed, it would take considerablymore force to press the diaphragm down and close the valve than it wouldrequire to hold the valve closed. Since the force which closes the valveis derived from expansion of the vapor in the thermal element, it wouldrequire a considerably higher temperature to close the valve than itwould require to keep the valve closed. Therefore the temperature of theroom would have to fall considerably after the valve closed before itgot low enough to allow the valve to re-open. Conversely, thetemperature would have to rise considerably above that at which thevalve opened in order to give the thermal element suflicient power toclose the valve. This difference between the closing and openingtemperatures is very materially reduced by the presence of gas underpressure in the chamber 18 when the valve 2123 is closed.

The difference between the opening and closing temperatues is furtherreduced by making the diameter of the seat 23 as large in proportion tothe diameter of the diaphragm as is practicable, and making the capacityof the port 25 rather limited. The full pressure of the gas is in thechamber 24 when the valve is closed, which, in view of the largediameter of this chamber, exerts a considerable tendency to lift thediaphragm. On the other hand, when the valve is open the gas pressureunder the whole diaphragm is considerably less than the pressure inchamber 24 when the valve is closed, because of the comparatively smallcapacity of the port 25, and the smallness of the flow of gas throughthe by-pass.

Making the seat 23 large in diameter serves another useful purpose, inthat a small movement of the diaphragm from the seat effects aconsiderable opening of the valve. It is this which enables the valve tobe operated directly with the thermal element, without the aid of leversor other mechanism for multiplying the movement of the thermal element.The metal disc 26 under the diaphragm contributes to this desideratum,by producing in the center of the diaphragm a rigid area as large as thediameter of the seat, thereby avoiding lost motion due to flexure of thedaphragm in the area enclosed by the ring 23 as the diaphragm is pressedto the seat by the thermal element. Thus I avoid mechanism havingrubbing friction or lost motion. Furthermore, the comparatively smallmovement of the diaphragm necessary to efiect a large opening of thevalve favors reduction of the diameter of the diaphragm with referenceto the diameter of the seat 23. Since the diaphragm need move but ashort distance to effect a large opening of the valve, the differencebetween the diameter of the seat and the diameter of the diaphragm maybe comparatively small without unduly restricting the movement of thediaphragm.

In addition to supporting the thermal element the spring 38 performsthe. important function of reducing, almost to the point of elimination,the effect on the thermal element due to changes in atmospheric weight(pressure). This results from concentration of the spring tension at thecenter of the thermal element. The ordinary variation in atmospherepressure will affect the expansion and contraction of the thermalelement at its central axis to an extent equal to a temperature changeof from 15 to 20 R, if no opposition to its expansion is present. I havefound that giving the spring 38 a tension such that, added to thepressure of the gas under the leather diaphragm, amounts toapproximately one-half pound, reduces the effect of ordinary variationsin atmospheric weight to the equivalent of about 1 of temperature.

In operation, and as the effect of the several features above describedtending to make the instrument very sensitive to comparatively smallchanges in temperature, the valve assumes a de gree of openness justlarge enough to maintain the temperature of the room at that for whichthe instrument is set.

It will be noticed that the entire thermal part of the instrument can beremoved as a unit without disturbing any adjustments. When it is thusremoved the action and general conditions of the diaphragm 21 can beascertained by inspection through the hole 45, and if necessary a newdiaphragm may be substituted, itbeing only necessary to remove thescrews 29 and lift off the plate 19. The heads of the screws 42 are madeto act as dowels to place the housing 36 in the correct position on theplate 19. To prevent reversing the position of the housing, one of thescrewheads is made too large to enter the hole provided for the otherhead.

While I have described and illustrated what I now regard as thepreferred embodiment of my invention, it is not to be supposed that itis limited in all of its details to the present structure, formodifications are possible without departure from the scope of myinvention as it is defined by the appended claims. What I claim is asfollows:

1. In a thermally actuated fluid-fuel regulator for a heater, a chamberconnected to the fuel supply, a chamber connected to the heater burner,a valve connecting said chambers, comprising an annular seat and aflexible diaphragm, the latter lying on the seat to close the valve,said diaphragm forming one wall of the second chamber, a bypass betweensaid chambers which permits the uninterrupted passage of a relativelysmall quantity of fuel to the second chamber, and a thermally actuatedelement whereby said diaphragm is moved to close said valve more or lesswhen the temperature of the surrounding atmosphere rises above apredetermined point, the circumference of said annular seat being largeenough so the thermal element will permit a suflicient opening of thevalve, the diaphragm being as small in diameter as possible withoutcausing the diaphragm instead of the thermal element to limit theopening of the valve.

2. In a thermally actuated fluid-fuel regulator for a heater, a chamberconnected to the fuel'supply, a chamber connected to the heater burner,a valve connecting said chambers, comprising an annular seat and aflexible diaphragm, the latter lying on the seat to close the valve,said diaphragm forming one wall of the second chamber, a by-pass betweensaid chambers which permits the uninterrupted passage of a relativelysmall quantity of fuel to the second chamber, a thermobellows-diaphragm,one Wall of which is stationary with reference to the valve seat, theother wall bearing against the diaphragm and adapted as the bellowsexpands to press the diaphragm toward or even to the seat, according tothe extent of the expansion, and a spring bearing against the movablewall of the bellows to oppose its expansion, whereby to reduce thevariation in the operation of the regulator due to variations in theweight of the atmosphere.

3. In a thermally actuated fluid-fuel regulator for a heater, a chamberconnected to the fuel supply, a chamber connected to the heater burner,and a valve connecting said chambers, comprising a seat and a flexiblediaphragm, the latter lying on the seat to close the valve, saiddiaphragm being subject to the pressure of the fuel in said secondchamber, which pressure tends to prevent the diaphragm from movingtoward said seat, said seat comprising a ring of large diameter comparedwith the diameter of the diaphragm, the ring forming a chamber which isconnected to said first mentioned chamber by a port so restricted insize that the fuel pressure under the diaphragm is less, when the valveis fully open, than the pressure in said first mentioned chamber.

4. In a thermally actuated fluid-fuel regulator for a heater, a chamberconnected to the fuel supply, a chamber connected to the heater, a valveconnecting said chambers, comprising a seat and a-flexible diaphragm,the latter lying on the seat to close the valve, a by-pass between saidchambers which permits the uninterrupted passage of a relatively smallquantity of fuel, and means whereby the fuel thus passed maintains arelatively small pressure under thediaphragm when the valve is closed;said valve seat comprising a ring of large diameter compared with thediameter of the diaphragm, the ring forming a chamber which is connectedto said first mentioned chamber by a port so restricted in size that thefuel pressure under the diaphragm is less, when the valve is fully open,than the pressure in said first mentioned chamber.

5. In a thermally actuated regulator for a heater, a housing theinterior of which is open to the atmosphere, a thermal expanding bellowssupported therein by being confined between the pointed end of anadjustment screw carried by one wall of said housing, which pointed endimpinges on the center of one wall of said bellows, and a flat elongatesheet metal spring, the ends of which are secured to opposite sides ofsaid housing, a pointed projection from the bellows wall impinging on asurface carried by said spring at a place intermediate the ends of thespring, said two impinging points being the sole support of saidbellows.

6. In a thermally actuated fuel regulator for a heater, a supportingmember, a thermo-bellows, having a depression in the center of one walland a stud projecting from the center of the opposite wall, an adjustingscrew carried by the supporting member, the point of which reposes insaid depression, and a guiding member carried by said supporting member,said guiding member carrying a socket in which said stud reposes, saidguiding member keeping the bellows in place and permitting the stud tomove to and fro as the bellows expands and contracts.

7. In a thermally actuated fuel regulator for a heater, a housing, athermo-bellows therein, having a. depression in the center of one walland a stud projecting from the center of the opposite wall; an adjustingscrew screwed into the top of the housing, the point of which reposes insaid depression, and a strip of metal secured'at its ends to oppositesides of the housing, carrying at its center a boss having a hole whichreceives said stud, said strip being flexible, thereby permitting thestud to move to and fro as the bellows expands and contracts, whileserving to support the bellows.

8. In a thermostatic controller, a bellows containing thermo-expansivefluid, opposite walls of the bellows being relatively movable inresponse to expansion or contraction of said fluid, the center of onewall impinging on the point of a fixed abutment, the center of theopposite wall having a pointed stem, 2. spring carrying a seat on whichthe point of said stem impinges, the spring and abutment forming thesole support for the bellows and maintaining the bellows in its properposition while allowing said opposite wall to move to and fro withreference to said fixed abutment.

9. In a thermostatic controller, a bellows filled with thermo-expansivefluid, opposite walls thereof being flexible and adapted to flex inresponse to expansion and contraction of said fluid in an axial linethat passes through the center of each of said walls, the center of onewall abutting a V-shape point on the end of an adjusting screw, whichscrew carries a pointer, a circular dial associated with said screw,said dial carrying a stud to engage the pointer and prevent excessiverotation of the screw, radial graduations on the dial spaced tocorrespond to the expansion of the bellows at different temperatures,meansfor rotating the dial on its axis and securing it in differentangular positions, so it will register correctly at a given temperature,and means for holding the center of the opposite wall of the bellows inalignment with the axis of said screw.

10. In a thermostatic controller, a bellows filled with thermo-expansivefluid, opposite walls thereof being flexible and adapted to flex inresponse to expansion and contraction of said fluid in an axial linethat passes through the center of each of said walls, the center of onewall abutting a V-shaped point on the end of an adjusting screw, whichscrew carries a pointer, a circular dial associated with said screw,said dial carrying a stud to engage the pointer and prevent excessiverotation of the screw, radial graduations on the dial spaced tocorrespond to the expansion of the bellows at different temperatures,means for rotating the dial on its axis and securing it in differentangular positions, so it will register correctly at a given temperature,and means for holding the center of the opposite wall of the bellows inalignment with the axis of said screw, said means permitting movement ofsaid wall to and fro without producing rubbing friction.

11 In a thermostatic controller, a bellows filled with thermo-expansivefluid, opposite walls thereof being flexible and adapted to flex inresponse to expansion and contraction of said fluid in an axial linethat passes through the center of each of said walls, the center of onewall abutting the V-shape point of an adjusting screw, which screwcarries a pointer, a circular dial associated with said screw, said dialcarrying a stud to engage the pointer and prevent exces-' sive rotationof the screw, radial graduations on the dial spaced to correspond to theexpansion of the bellows at different temperatures, means for rotatingthe dial on its axis and securing it in different angular positions, soit will register correctly at a given temperature, means for holding thecenter of the opposite wall by means of a V-shape point in alignmentwith the axis of said screw, and means for imposing a force on phragmand a circular valve seat therefor, said F valve seat being large indiameter with reference to the diameter of the diaphragm. whereby toeffect a large opening of the valve with a small movement of thediaphragm, means connecting one of said terminals to an abutment whichis fixed relative to said seat and the other terminal to the diaphragm,whereby to effect relative movement between the seat and diaphragm equalto the relative movement of the terminals, and means for effecting saidmovement without rubbing friction, the connection to the diaphragm beingin the center of the valve seat and in the nature of a universal joint,thereby insuring level seating of the diaphragm on the seat.

13. In a graduated action thermostatic fuel valve, an inlet chamber, anoutlet chamber and a passage having a valve seat therebetween, aflexible diaphragm adapted to move to and from said valve seat andhaving a valve member to fit said seat, said diaphragm forming one wallof said outlet chamber, fuel pressure in said cham-' ber tending to movesaid diaphragm away from the valve seat; a flexible expansion memberexposed to atmospheric temperature and adapted upon expansion to pushthe diaphragm toward the valve seat, the periphery of the valve seatbeing comparatively large to give required opening area with small lift,the radial distance from said valve member to the perimeter of thediaphragm being only great enough to permit the required valve-memberlift, whereby the .area of the diaphragm externally of the valve seat isreduced to the minimum, and a by-pass for fuel from said inlet chamberto the outlet chamher, which fuel is designed to maintain as nearlyuniform lifting pressure under the diaphragm as possible.

14. In a fuel regulator, a thermal element having two terminalsrelatively movable in response to temperature changes, a valvecomprising a flexible diaphragm and a seat therefor, means connectingone of said termina s to an abutment which is fixed relative to sai seatand the other terminal to the diaphragm, ach connection being in thenature of a universal joint, whereby to effect relative movement betweensaid seat and diaphragm equal to the relative movement of theterminalsyand means independent of the diaphragm for'guiding theterminal connected to the diaphragm.

15. In a fuel regulator, a thermal element having two terminalsrelatively movable in response to temperature changes, a valvecomprising .a flexible diaphragm and a seat therefor, means connectingone of said terminals to an abutment which is fixed relative to saidseat and the other terminal to the diaphragm, each connection being inthe nature of a universal joint free from rubbing friction, whereby toeffect relative movement of the terminals, and means independent of thediaphragm for guiding the terminal connected to the diaphragm.

16. In a fuel regulator, a thermal element having two terminalsrelatively movable in response to temperature changes, a valvecomprising a flexible diaphragm and a ring acting as a seat therefor,the portion of the diaphragm which coacts with said seat being rigid,means connecting one of said terminals to said seat, a spring carrying amember having two flat surfaces parallel to each other and perpendicularto a line passing through said terminals, said spring pressing one ofthe flat surfaces of said member against the remaining terminal, therebyinsuring that said member will move to and fro in unison with theterminal when the latter moves in response to temperature changes, theopposite surface bearing against the diaphragm and pressing thediaphragm to its seat when the thermal element expands sufficiently, thespring serving as the sole guide for said member, thereby avoidingrubbing friction.

17. In a gas regulator, a thermal element having two terminalsrelatively movable toward and from each other in response, respectively,to reductions and increases in the temperature of the atmospheresurrounding said element, a valve comprising a flexible diaphragm and aring acting as a seat therefor, the interior of the ring being subjectto gas pressure capable of pressing the diaphragm away from the ring inthe absence of a superior counter pressure, the area of the diaphragmwhich coacts with the seat being rigid, means connecting one of saidterminals with said ring, the remaining terminal consisting of a pointedstud, a flat spring supported at its ends. and at its center carrying aboss provided with a hole having a flat bottom, which bottom isperpendicular to the line wherein said stud moves in response totemperature changes and is pressed against the point of the stud by thetension of the spring, the bottom of the boss, which is parallel to thebottom of said hole, being so positioned with reference to the diaphragmthat it bears against a button in the center of said rigid area of thediaphragm and presses the diaphragm to the seat when the temperature ofthe atmosphere reaches the point at which it is desired to cut off thegas.

18. In a gas regulator, a thermal element having two terminalsrelatively movable toward and from each other in response, respectively,to reductions and increases in the temperature of the atmospheresurrounding said element, a valve comprising a flexible diaphragm and aring acting as a seat therefor, the interior of the ring being subjectto gas pressure capable of lifting the diaphragm in the absence of asuperior counter pressure, means connecting one of said terminals tosaid ring, said means comprising an adjusting screw against which saidterminal bears, the remaining terminal consisting of a pointed stud, aflat spring supported at its ends at its center having a socket toreceive the point on said stud, the tension of the spring beingtoward-said adjusting screw, thereby supporting the thermal elementbetween two points, the opposite side of the spring having a partadapted to press the diaphragm to the seat when the temperature of theatmosphere reaches a given point; a circular graduated dial throughwhich said adjusting screw passes and a pointer carried by said screw topoint to said graduations, the graduations being differentially spacedto accord with variations in the distance the terminals move atdifferent temperatures in response to equal temperature changes.

19. In a thermally actuated regulator for a heater, a body containing achamber connected to the fuel supply and a chamber connected to theheater burner, a valve connecting said chambers comprising a flexiblediaphragm, a cover for said diaphragm, said cover being secured to saidbody; a housing carrying a thermal mechanism, said housing beingremovably secured to said cover, the thermal mechanism comprising amember which passes through a hole in said cover when the housing isconnected to the cover and establishes an operative connection betweenthe diaphragm and the thermal mechanism, said housing being removableand replaceable without disturbing the adjustment of the thermalmechanism.

20. In a thermally actuated regulator for a heater, a body containing achamber connected to the fuel supply and a chamber connected to theheater burner, a valve connecting said chambers comprising a flexiblediaphragm, a housing carrying a thermal mechanism, said housing having asmooth surface which rests upon and is se- 'screws, the-housing beingremovable from and attachable to said surface without disturbing thediaphragm or changing the adjustment of the thermal mechanism, and meanswhereby putting the housing in place automatically establishes anoperative connection between the diaphragm and said thermal mechanism.

21. In a thermally actuated regulator for a heater, a body containing achamber connected to the fuel supply and a chamber connected to theheater burner, a valve connecting said chambers comprising a flexiblediaphragm, a housing carrying a thermal mechanism, said housing having asmooth surface which rests upon and is secured to a smooth surfacecarried by the body by screws, the housing being removable from andattachable to said surface without disturbing the diaphragm 'or changingthe adjustment of the thermal mechanism, means whereby putting thehousing in place automatically establishes an operative connectionbetween the diaphragm and said thermal mechanism, andmeans forpreventing replacement of the housing in other than the same positionrelative to the body that it previously occupied.

22. In a thermally actuated regulator for aheater, 9. body containing achamber connected to the fuel supply and a chamber connected to theheater burner, a valve connecting said chambers comprising a flexiblediaphragm, a cover for said diaphragm, said cover being secured to saidbody, a housing secured to said member and containing a thermalmechanism comprising a spring that extends like a bridge across thehousing and being secured thereto by two screws one at each end of thespring, said heads being of different diameters, holes in said memberinto which said screw heads enter to serve as dowels, the holes beingalso of different diameters so the housing can be placed on the cover inonly one way, and means whereby putting the housing in place on saidmember automatically connects the thermal mechanism to the diaphragm,all to the end that the thermal mechanism can be removed and re-= placedwithout changing or disturbing its adjustment.

23. In combination, a valve for regulating the flow of fuel to a heater,a thermally actuated element, means whereby said element moves the valveto various degrees of closure according to changes in the temperature ofthe atmosphere surrounding the element, said .valve being opened by thepressure of the fuel, means for adjusting the relationship between thevalve and said element, whereby to maintain said surrounding atmosphereat substantially a predetermined temperature, said means comprising acircular dial carrying a graduated scale indicating temperatures and apointer mounted in the center thereof and revoluble with referencethereto to point to any graduation thereon, the graduations on said dialbeing differentially spaced, said dial being itself revoluble by way ofinitial adjustment to bring into registration with the pointer thegraduation which represents the temperature at the moment surroundingthe thermally actuated element.

24. In combination, a valve for regulating the flow of fuel to a heater,a thermally actuated element, means whereby said element moves the valveto various degrees of closure according to changes in the temperature ofthe atmosphere surrounding the element, said valve being opened by thepressure of the fuel and means for adjusting the relationship betweenthe valve and said element, whereby to maintain said surroundingatmosphere at substantially a predetermined temperature, said meanscomprising a circular dial carrying a graduated scale indicatingtemperatures and a pointer mounted in the center thereof and revolublewith reference thereto to point to any graduation thereon, thegraduations on said dial being differentially spaced, said dial beingitself revoluble by way of initial adjustment to bring into registrationwith the pointer the graduation which represents the temperature at thatmoment surrounding the thermally actuated element, and a stud carried bythe dial in the path of the pointer to limit the movement of the latterto a single revolution around the dial.

25. In a thermostatic controller, a bellows filled with expansive fluid,opposite walls thereof being adapted to move toward and from each otherin response to expansion and contraction of said fluid, one wallabutting a point on an adjusting screw which carries a pointer, a dialassociated with said screw, radial graduations on the dial representingtemperatures at which it may be desirable tomaintain the atmospheresurrounding the bellows, said graduations being differentially spaced,the opposite wall of the bellows abutting the member to be controlled bythe bellows, said dial being revoluble about the adjustingscrew by wayof initial adjustment of the controller.

26. In a thermally actuated fluid-fuel regulator for a heater, a chamberconnected to the fuel supply, a chamber connected to the heater burner,

a third chamber, a valve connecting said first and third chambersthrough a port no larger than necessary to pass enough gas to supply theburner,

and a thermally actuated element whereby said j diaphragm is moved toclose said valve more or less when the temperature of the surroundingatmosphere rises above a predetermined point, the circumference of saidannular seat being large enough so the thermal element will permit asufli- '3 cient opening of the valve, the diaphragm being as small indiameter as possible without causing the diaphragm instead of thethermal element to limit the opening of the valve.

OTTO J. KUENHOLD.

